// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "src/ast/source-range-ast-visitor.h"

#include "src/ast/ast-source-ranges.h"

#include "src/objects-inl.h" // weolar

namespace v8 {
namespace internal {

    SourceRangeAstVisitor::SourceRangeAstVisitor(uintptr_t stack_limit,
        Expression* root,
        SourceRangeMap* source_range_map)
        : AstTraversalVisitor(stack_limit, root)
        , source_range_map_(source_range_map)
    {
    }

    void SourceRangeAstVisitor::VisitBlock(Block* stmt)
    {
        AstTraversalVisitor::VisitBlock(stmt);
        ZonePtrList<Statement>* stmts = stmt->statements();
        AstNodeSourceRanges* enclosingSourceRanges = source_range_map_->Find(stmt);
        if (enclosingSourceRanges != nullptr) {
            CHECK(enclosingSourceRanges->HasRange(SourceRangeKind::kContinuation));
            MaybeRemoveLastContinuationRange(stmts);
        }
    }

    void SourceRangeAstVisitor::VisitFunctionLiteral(FunctionLiteral* expr)
    {
        AstTraversalVisitor::VisitFunctionLiteral(expr);
        ZonePtrList<Statement>* stmts = expr->body();
        MaybeRemoveLastContinuationRange(stmts);
    }

    bool SourceRangeAstVisitor::VisitNode(AstNode* node)
    {
        AstNodeSourceRanges* range = source_range_map_->Find(node);

        if (range == nullptr)
            return true;
        if (!range->HasRange(SourceRangeKind::kContinuation))
            return true;

        // Called in pre-order. In case of conflicting continuation ranges, only the
        // outermost range may survive.

        SourceRange continuation = range->GetRange(SourceRangeKind::kContinuation);
        if (continuation_positions_.find(continuation.start) != continuation_positions_.end()) {
            range->RemoveContinuationRange();
        } else {
            continuation_positions_.emplace(continuation.start);
        }

        return true;
    }

    void SourceRangeAstVisitor::MaybeRemoveLastContinuationRange(
        ZonePtrList<Statement>* statements)
    {
        if (statements->is_empty())
            return;

        Statement* last_statement = statements->last();
        AstNodeSourceRanges* last_range = nullptr;

        if (last_statement->IsExpressionStatement() && last_statement->AsExpressionStatement()->expression()->IsThrow()) {
            // For ThrowStatement, source range is tied to Throw expression not
            // ExpressionStatement.
            last_range = source_range_map_->Find(
                last_statement->AsExpressionStatement()->expression());
        } else {
            last_range = source_range_map_->Find(last_statement);
        }

        if (last_range == nullptr)
            return;

        if (last_range->HasRange(SourceRangeKind::kContinuation)) {
            last_range->RemoveContinuationRange();
        }
    }

} // namespace internal
} // namespace v8
